LAPIS Semiconductor ML610421, User Manual, Page: 269 / 437

ML610Q421/ML610Q422/ML610421 User’s Manual
Chapter 20 Port 3
20 – 10
20.3 Description of Operation
20.3.1 Input/Output Port Functions
For each pin of Port 3, either output or input is selected by setting the Port 3 direction register (P3DIR).
In output mode, high-impedance output mode, P-channel open drain output mode, N-channel open drain output mode,
or CMOS output mode can be selected by setting the Port 3 control registers 0 and 1 (P3CON0 and P3CON1).
In input mode, high-impedance input mode, input mode with a pull-down resistor, or input mode with a pull-up resistor
can be selected by setting the Port 3 control registers 0 and 1 (P3CON0 and P3CON1).
At a system reset, high-impedance output mode is selected as the initial state.
In output mode, “L” or “H” level is output to each pin of Port 3 depending on the value set by the Port 3 data register
(P3D).
In input mode, the input level of each pin of Port 3 can be read from the Port 3 data register (P3D).
20.3.2 Secondary and Tertiary Functions
Secondary and tertiary functions are assigned to Port 3 as the RC-ADC (channel 0) oscillation pins (IN0, CS0, RS0,
RT0, RCT0, RCM) and the PWM output pin (PWM0). These pins can be used in a secondary or tertiary function
mode by setting the P35MD0 to P30MD0 bits and the P35MD1 to P30MD1 bits of the Port 3 mode registers (P3MOD0,
P3MOD1).
Note:
All the port 3 pins except P35/RCM are configured as pins dedicated to the RC-ADC function during A/D conversion.
Therefore, if there is any unused pin, that pin cannot be used as its primary function during A/D conversion. For the
RC-ADC, see Chapter 24, “RC Oscillation Type A/D Converter”.